chore(deps): bump soroban-sdk from 23.5.2 to 25.3.1 in /stellar-lend

Bumps [soroban-sdk](https://github.com/stellar/rs-soroban-sdk) from 23.5.2 to 25.3.1.
- [Release notes](https://github.com/stellar/rs-soroban-sdk/releases)
- [Commits](stellar/rs-soroban-sdk@v23.5.2...v25.3.1)

---
updated-dependencies:
- dependency-name: soroban-sdk
  dependency-version: 25.3.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]